Excess mortality among persons with severe mental illness (SMI) is documented consistently, yet higher suicide rates only partially explain this mortality difference. Previous research has focused little attention on the contribution of somatic disease or poor quality care to mortality in persons with SMI, who likely are at higher risk than others for poorer quality care, including adverse events. This study will utilize and extend an existing NIMH-funded community-based cohort of 6,235 adults with SMI, ages 21-62 in 1993, enrolled in Maryland Medicaid, and followed from fiscal years 1994-2000. Matching to the National Death Index revealed over 18% (N=1142) have died at a mean age of only 51 years. This magnitude of early mortality, almost 3 times the expected rate for Maryland residents, is alarming. A retrospective study is proposed to examine potentially preventable causes of mortality in persons with SMI. In Maryland Medicaid cohorts of 6,235 adults with SMI and 30,000 disabled adults without SMI our Specific Aims are: 1) Estimate the relative risk of mortality from specific health problems (alcohol and substance abuse, injury and chronic medical conditions); 2) Examine the relative risk of mortality associated with poor quality of care for coronary artery disease, diabetes, schizophrenia, bipolar disorder and major depression. In the SMI cohort we will then: 3) Examine the risk of in-hospital mortality or mortality within 30 days of hospital discharge associated with the occurrence of adverse events in medical and surgical hospitalizations; and 4) Compare the occurrence and types of adverse events to a completed state-of-the art patient safety study of admissions to general hospitals. Specific Aims 1 and 2 will implement a longitudinal analysis of Medicaid administrative data through 2004 and apply quality of care indicators for chronic conditions. Specific Aim 3 will use a case-crossover design where adverse events from hospital records around the time of death will be compared to those in a randomly selected earlier hospitalization for the same subject. Specific Aim 4 will compare adverse event data in Specific Aim 3 to a patient safety study in the general population using the same chart abstraction instrument. This innovative study will illuminate factors contributing to premature death in the SMI that may be amenable to improved quality of care, and/or improved patient safety, and will provide a basis for prioritizing interventions to improve longevity in the SMI.